This application claims the priority of German Patent Application 199 20 052.1, filed May 3, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a suspension for a front drive assembly of a motor vehicle, with the drive unit being aligned in the lengthwise direction of the vehicle and supported by elastic mounts on the vehicle body.
A four-point suspension for a drive assembly of a motor vehicle on a subframe is known from U.S. Pat. No. 5,074,374, with the subframe being fastened to the vehicle body by an elastic mount. Another mount is provided on the transmission housing.
A goal of the invention is to create a suspension for a drive unit of a motor vehicle for an off-road vehicle that is secured to the vehicle body in a functionally separate and independent fashion by a corresponding subframe in a manner that is as free as possible of vibration and can be fastened with the subframe as a modular unit to the vehicle body and also provides additional stiffening of the front end of the vehicle.
This goal is achieved, according to the invention, by a suspension of the above-noted type, comprising a pair of vehicle side frame members spaced laterally from one another,
a subframe which in use supports wheel suspension assemblies, said subframe being supported at undersides of the respective side frame members,
an engine support cross member which is separate from the subframe and connected with the side frame members, said engine support cross member having two elastic engine mounts operable to support the engine housing above the subframe, and
a transmission support cross member connected with the side members and having an elastic transmission mount operable to support the transmission housing,
wherein the subframe is connected with the side frame members by elastic mounts operable to permit transverse and longitudinal movement of the subframe with respect to the side members.
The drive assembly is supported above a subframe on a separate engine cross member by two elastic mounts with receptacles or the like on the engine housing. A third mount is provided on the transmission housing or on the distributor transmission housing and is supported on a transmission cross member connected with side members.
The fastening mount of the subframe, located forward relative to the direction of travel of the vehicle, is attached together with the engine cross member to side members of the vehicle. In particular, this engine cross member is connected rigidly at its free ends with the side members of the vehicle body subframe is held by separate elastic mounts, with interposition of the cross member, to the side members of the vehicle body and has a certain degree of elastic mobility.
To attach the subframe and the engine cross member, a continuous mounting bolt is used which passes through a first spacing bushing in the elastic mount of the subframe, passes through a second spacing bushing in the engine cross member, and is secured in a threaded bushing of the side member.
An offset mount bracket is mounted to receive the engine mounts at the free ends of the engine cross member, said bracket also having a fastening provision for the engine cross member on the side members. In addition to the direct fastening of this cross member by its free ends to the side members, an additional mounting provision is provided at a lengthwise distance from the first mount.
The engine cross member is made offset between the side members with this offset being located approximately in a horizontal plane with the cross members of the subframe so that the engine housing is located lower down and its position is not interfered with.
Since the subframe and the engine cross member are fastened separate from one another to the side members relative to the elastic mount of the subframe, a functional separation can be created between the subframe suspension and the engine suspension, so there can be no influence of the various assemblies and excitations on the subframe. In addition, a subframe can be used for different engines with the cross member being adaptable to the various engines with regard to the engine mounts. In addition, the front end of the vehicle is made stiffer by the engine cross members as a result of the rigid connection to the side members. The essential inventive advantage is therefore that an optimum amount of play for mounting the engine mounts can be produced with the cross member being replaceable by another cross member with a corresponding arrangement of the engine mounts.
The engine mounts, according to certain preferred embodiments of the invention, are located immediately adjacent to the engine housing at an approximately equal distance from the lengthwise central axis of the assembly. A transmission mount is located in a vertical plane that runs approximately through the lengthwise central axis. The three mounts are located on a common plane that rises diagonally forward, with this plane being located below a horizontal center of gravity plane. The engine mounts are located in the vicinity of a vertical center of gravity plane, with the transmission mount being located at a considerable distance from the vertical center of gravity plane. The transmission mount is located at a greater distance from the vertical center of gravity plane than the two engine mounts.
The arrangement of the engine mounts and the transmission mounts is chosen essentially so that no significant vibration can spread from the drive assembly to the body.